Real-Time Visualizing Mitophagy-Specific Viscosity Dynamic by Mitochondria-Anchored Molecular Rotor

Area of Science:

• Cell Biology
• Biochemistry
• Molecular Imaging

Background:

• Mitophagy is a vital cellular process for maintaining metabolic and physiological health.
• While environmental factors like pH and polarity in mitophagy are known, the dynamic changes in viscosity within live cells remain unexplored.
• Understanding these dynamics is crucial for comprehending mitophagy's role in cellular health and disease.

Purpose of the Study:

• To develop and validate a novel fluorescent probe for real-time imaging of viscosity changes during mitophagy in live cells.
• To investigate the dynamic viscosity alterations within mitochondria during the mitophagy process.
• To establish a new tool for studying mitochondrial diseases.

Main Methods:

• Synthesis and characterization of a mitochondria-targetable molecular rotor, ethyl-4-[3,6-bis(1-methyl-4-vinylpyridium iodine)-9 H-carbazol-9-yl)] butanoate (BMVC).
• Utilizing BMVC as a fluorescent viscosimeter to monitor viscosity changes in the mitochondrial microenvironment.
• Real-time imaging of mitophagy under nutrient starvation conditions.

Main Results:

• BMVC functions effectively within the mitochondrial microenvironment, exhibiting an 'off-on' fluorescence response to viscosity.
• The study discovered that mitochondrial viscosity significantly increases during the mitophagy process.
• Successful real-time visualization of mitophagy dynamics was achieved.

Conclusions:

• The developed BMVC probe enables effective imaging of viscosity variations during mitophagy.
• Increased mitochondrial viscosity is a newly identified characteristic of the mitophagy process.
• BMVC is a promising tool for investigating the pathogenic mechanisms of mitochondrial diseases.